Photosynthetic characteristics of cotton are enhanced by altering the timing of mulch film removal

Table 6 Parameters for the logistic equation of two cotton varieties’ (XLZ42 and XLZ45) dry matter accumulation in various treatments groups: Mulch film was removed at 1 and 10 days before the first irrigation (T1(June 4, 2015, June 19, 2016 and June 10, 2017), T10(May 25, 2015, June 9, 2016 and May 31, 2017), respectively) and 1 day before the second irrigation (E1(June 14, 2015, June 29, 2016 and June 20, 2017)) after seedling emergence, during 2015–2017. The control group (CK) was film mulched throughout the growth stage

Varieties and Years	Treatments	K	a	b	R²	Tmax /d	t1 /d	t2 /d	Rmax /(kg·ha⁻¹·d⁻¹)	Wm /(kg·ha⁻¹)	△W_t2-_t1 /(kg·ha⁻¹)
XLZ42, 2015	CK	28 448.19	4.5183	−0.0440	0.9813**	103	73	133	313.14	14 224.10	8 207.30
	E1	13 546.26	3.6292	−0.0416	0.9780**	87	56	119	140.86	67 73.13	3 908.10
	T1	98 03.42	3.7293	−0.0505	0.9566**	74	48	100	123.86	49 01.71	2 828.29
	T10	13 098.11	4.1369	−0.0478	0.9955**	87	59	114	156.55	65 49.06	3 778.81
XLZ42, 2016	CK	15 233.50	4.8979	−0.0732	0.9866**	67	49	85	278.86	7 616.75	4 394.86
	E1	15 730.68	4.9953	−0.0686	0.9889**	73	54	92	269.84	7 865.34	4 538.30
	T1	18 790.06	4.4678	−0.0554	0.9953**	81	57	104	260.43	9 395.03	5 420.93
	T10	11 573.49	5.2355	−0.0786	0.9933**	67	50	83	227.49	5 786.75	3 338.95
XLZ45, 2016	CK	26 514.86	3.9347	−0.0396	0.9467**	99	66	133	262.48	13 257.43	7 649.54
	E1	19 615.03	4.7176	−0.0635	0.9969**	74	54	95	311.55	9 807.51	5 658.93
	T1	30 025.95	4.2929	−0.0460	0.9612**	93	65	122	345.06	15 012.98	8 662.49
	T10	15 532.38	4.5283	−0.0597	0.9794**	76	54	98	231.63	7 766.19	4 481.09
XLZ42, 2017	CK	19 068.20	4.3338	−0.0457	0.9728**	95	66	124	217.82	9 534.10	5 501.17
	E1	24 279.73	4.5090	−0.0443	0.9943**	102	72	132	268.67	12 139.86	7 004.70
	T1	12 510.99	4.3294	−0.0516	0.9790**	84	58	109	161.48	6 255.49	3 609.42
	T10	20 762.82	4.7209	−0.0476	0.9964**	99	72	127	247.01	10 381.41	5 990.07
XLZ45, 2017	CK	14 775.97	4.5932	−0.0572	0.9719**	80	57	103	211.11	7 387.99	4 262.87
	E1	14 817.38	4.6920	−0.0551	0.9969**	85	61	109	204.16	7 408.69	4 274.82
	T1	18 182.35	4.6752	−0.0520	0.9915**	90	65	115	236.46	9 091.17	5 245.61
	T10	12 452.72	4.8122	−0.0592	0.9940**	81	59	104	184.18	6 226.36	3 592.61

Note: k, a, and b are equation coefficients
Tmax, the time when the dry matter accumulation rate reached a maximum
t1, starting time of linear accumulation
t2, end time of linear accumulation
Rmax, the maximum accumulation rate
Wm, dry matter weight at the time when the dry matter accumulation rate reached a maximum
△Wt2-t1, dry matter accumulation from t1 to t2. R2, Correlation Index
* Significant at the 0.05 probability level. ** Significant at the 0.01 probability level

ISSN: 2523-3254